Recently, mobile apps have been proposed that utilize ultrasonic sound waves (ultrasound) to transmit data among devices using the device's speaker and microphone. This technology, referred to as ultrasonic networking can transmit data at inaudible frequencies not perceptible to the humans. While this technology has potential for use in various applications because it allows for near field communications without additional hardware, ultrasound networking opens the door to potential data leaks in which malware loaded onto a mobile device can use ultrasound to illicitly transmit confidential information stored on the device.
Currently, firewalls exist to monitor and block illicit data transfers involving traditional communication schemes such as WIFI, LTE, 3G, 2G, Edge and Bluetooth. However, no such technology exists for ultrasonic networking.